Wound hoses, especially in the form of spiral wound metallic hoses, are used for conducting fluids (exhaust gases) especially in motor vehicles. These hoses are not leakproof. In order to achieve full tightness, they are used as inliners in a bellows or a corrugated hose having uncoupling elements. It is desirable to minimize the temperature losses in the exhaust gas flowing through the wound hose and, on the one hand, to protect a surrounding bellows against the hot exhaust gases, which have a temperature of 400° C. to 550° C. there, and, on the other hand, to keep the exhaust gas temperature high in this case and also when using a wound hose as a single conduction element for the later aftertreatment for the purpose of reducing foreign substances, such as by means of catalysts, since such an aftertreatment is better or particularly effective at higher temperatures.
For creating a heat-insulated wound hose, a suggestion was already made to form such a hose from at least two separate profiled strip layers, which are wound together, whereby one layer consists of metal and the other consists of heat-insulating material; the latter was preferably inserted between two metal strip layers in a sandwich-like pattern. While a wound hose formed in this manner creates a good heat insulation, it is very costly to manufacture; also, wound hoses with the three said layers—metal on the outside in each—case are necessary in practical terms, since heat-insulating material with high coefficients of friction would otherwise cause friction on one another.
A major drawback of the prior-art process is, moreover, that in a profiled strip material consisting of multilayer flat strip material with at least one metal layer and one insulating layer, especially if this is ceramic, which is needed for manufacturing the wound hose, because of the profiling process and especially when folding the strip layer, the insulating layer may tear and peel off from the metal layer, such that waste forms and/or the insulating layer in the finished wound hose is interrupted.